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Adhesives Urea Formaldehyde (UF)

Pizzi (1994) suggested that UF adhesive polymer is the result of condensation reaction of formaldehyde with urea. Advantages of UF adhesives include water soluble, hard, non-flammable, good heat properties, colorless when hardened, and the price is cheap. Hiziroglu (2007) suggested some of the characteristics of the adhesive Urea-Formaldehyde (CH4 N20CH20) x among others:
o Gravity: 1:27
o Solid content: 64.8%

Vick (1999) suggested that there is a UF adhesive powder or liquid, white, colorless adhesive lines and more durable when combined with melamine. This is the use of adhesive for plywood, furniture, fiber board and particle board. Tsoumis (1991) suggested that UF is available daalam liquid or powder form. This Resain 95-1 hardened at a temperature of 30 C. UF is not suitable for exterior.

However, its performance can be improved with the addition of Melamine Formaldehyde or Formaldehyde Resorcynol about 10-20%. Results connection with UF colorless to light brown color. The downside of UF, among others, are not waterproof and cause formaldehyde emissions that impact on health. UF adhesives are included in the group of thermosetting adhesive. In its use is often added hardener, filler, extender and water.

According to Rayner (1967) in Joyoadikusumo (1984) UF adhesives have excellent resistance to cold water, somewhat resistant to hot water, but not resistant to boiling. After that, if made of plywood 3 layers, specifically for finir which will serve as the core whitewash both surfaces with glue / adhesive through the machine glue spreader, while finir-finir the other (F / B) attached to finir which has given the adhesive with the provisions direction the fibers are perpendicular to each other.

Furthermore finir-finir that have been glued together the (finir must be an odd number) are cold-pressed in a cold press for 5-15 minutes, the pressure of 10- 15 kg / cm2, and then followed by compression in the heat in a hot press to enter the finir-finir which has been glued in between the hot steel plates with a pressure of 10 kg / cm2, temperature of 100 to 170o (generally 110 to 120o C) for 1.5 minutes.
After that rekatan finir (candidate plywood) are removed from the hot press machine one by one in order to obtain plywood (plywood).

Plywood further cut edges corresponding to the final size of the saw cut double (double s), then smoothed (sanding) and checked the quality (grading plywood). If still found damage (tear or hole) and enabling improved then the face of the plywood is then repaired again with caulked so that the quality plywoodnya increased.

How to sawmill
Is the oldest way and they are very rarely used, because finirnya thick enough that at least 5 mm. Wood is used in the form of a square timber and the yield is low. Even if there can only be found in small industry. Sawing process using circular sawing of veneer or horizontal gang of saw for veneer.

How to perautan
Finir way of making this principle is like sharpening a pencil (a pencil is an analogy logs without bark). This method is now abandoned and not developed.